Recently, various chairs of which body-supporting surface is made of a fabric mesh sheet such as knitted cloth and woven cloth so that good cushioning properties are achieved without urethane foam or the like have been sold in the open market while new configurations have been suggested as disclosed in JP 2007-117537-A and JP 2006-132047-A. JP 2007-117537-A discloses a chair structure of which a backrest is made of sheet material provided with bag-formed hems into which core members are inserted to make a frame supporting itself. JP2006-132047-A discloses another seat structure of which the seating face is made of warp knit knitted by a double raschel knitting machine. Further, an office chair and a vehicle seat, made from a mesh fabric containing a sheet elastomer of fiber having high extensibility such as elastomer fiber, have been suggested.
Furthermore, JP 2001-159052-A discloses a cushion material made from a fabric provided with elastomer fiber weft yarn and polyester fiber warp yarn to achieve both good extensibility and strength.
From such viewpoints, desired are an advanced space-saving material having excellent cushioning properties and proper amount of sinking.
As to materials made with a large amount of conventional elastomer as shown in JP 2007-117537-A or JP 2006-132047-A, stability or comfort is not secured because the materials might stretch too much when unexpectedly high load is applied, even though high extensibility is achieved.
The material disclosed in JP 2001-159052-A has only poor stretch properties along polyester fibers so that a proper amount of sinking cannot be achieved. Further, unexpectedly high load might cause a stress to deform the elastomer over the yield point although it extends well along the elastomers.
Furthermore, the fabric has unidirectionally high extensibility and, therefore, if the warp and weft directions of the fabric are fixed the extensibility might be poor.
Accordingly, it could be helpful to provide a stretch fabric for seats, which is excellent in cushioning properties and is used as a space-saving material serving both as a holding material and a cushioning material.